As far as I can see, your examples for shellsend are bad/broken

e.g.

[size=10pt][font=courier]shellsend.exe "user@host.com" "user@host.com" "smtp.gmail.com" "465" "1" "username@domain.com" "mypassword" "C:\File.txt"
This will send the contents of the file "C:\File.txt" to "user@host.com" through SMTP port 465 while using SSL and logging in as "username@domain.com" using the password "mypassword".
[/font][/size]

that didn't work, but the following syntax did:

shellsend.exe "user@host.com" "user@host.com" "smtp.gmail.com" "465" "1" "gmailusername" "gmailpassword" "subjectline" "C:\File.txt"

- username@domain is not relevant to a gmail example like this, just put "username" please
- subjectline was missing, so the syntax as per your example fails.

Maybe you could put a few more examples in also (but please check they work also !).

Regards,

Roy